Contrary to what we may imagine about the impact of climate change in Europe, a colder future may be in store. In a new study, researchers from the University of Copenhagen’s Niels Bohr Institute and Department of Mathematical Sciences predict that the system of ocean currents which currently distributes cold and heat between the North Atlantic region and tropics will completely stop if we continue to emit the same levels of greenhouse gases as we do today.

Using advanced statistical tools and ocean temperature data from the last 150 years, the researchers calculated that the ocean current, known as the Thermohaline Circulation or the Atlantic Meridional Overturning Circulation (AMOC), will collapse — with 95 percent certainty — between 2025 and 2095. This will most likely occur in 34 years, in 2057, and could result in major challenges, particularly warming in the tropics and increased storminess in the North Atlantic region.

“Shutting down the AMOC can have very serious consequences for Earth’s climate, for example, by changing how heat and precipitation are distributed globally. While a cooling of Europe may seem less severe as the globe as a whole becomes warmer and heat waves occur more frequently, this shutdown will contribute to an increased warming of the tropics, where rising temperatures have already given rise to challenging living conditions,” says Professor Peter Ditlevsen from the Niels Bohr Institute.

“Our result underscores the importance of reducing global greenhouse gas emissions as soon as possible,” says the researcher.

The calculations, just published in the scientific journal, Nature Communications, contradict the message of the latest IPCC report, which, based on climate model simulations, considers an abrupt change in the thermohaline circulation very unlikely during this century.

Early warning signals present

The researchers’ prediction is based on observations of early warning signals that ocean currents exhibit as they become unstable. These Early Warning Signals for the Thermohaline Circulation have been reported previously, but only now has the development of advanced statistical methods made it possible to predict just when a collapse will occur.

The researchers analysed sea surface temperatures in a specific area of the North Atlantic from 1870 to present days. These sea surface temperatures are “fingerprints” testifying the strength of the AMOC, which has only been measured directly for the past 15 years.

“Using new and improved statistical tools, we’ve made calculations that provide a more robust estimate of when a collapse of the Thermohaline Circulation is most likely to occur, something we had not been able to do before,” explains Professor Susanne Ditlevsen of UCPH’s Department of Mathematical Sciences.

The thermohaline circulation has operated in its present mode since the last ice age, where the circulation was indeed collapsed. Abrupt climate jumps between the present state of the AMOC and the collapsed state has been observed to happen 25 times in connection with iceage climate. These are the famed Dansgaard-Oeschger events first observed in ice cores from the Greenlandic ice sheet. At those events climate changes were extreme with 10-15 degrees changes over a decade, while present days climate change is 1.5 degrees warming over a century.

Facts:

• The Atlantic Meridional Overturning Circulation (AMOC) is part of a global system of ocean currents. By far, it accounts for the most significant part of heat redistribution from the tropics to the northernmost regions of the Atlantic region — not least to Western Europe.
• At the northernmost latitudes, circulation ensures that surface water is converted into deep, southbound ocean currents. The transformation creates space for additional surface water to be moved northward from equatorial regions. As such, thermohaline circulation is critical for maintaining the relatively mild climate of the North Atlantic region.
• The work is supported by TiPES, a joint-European research collaboration focused on tipping points of the climate system. The TiPES project is an EU Horizon 2020 interdisciplinary climate research project focused on tipping points in the climate system.

In September 2019, Virginia Tech Transportation Institute (VTTI) began the first large-scale naturalistic driving study of electric scooter, also known as e-scooter, riders. Over the span of 18 months, 50 scooters, equipped with forward-facing cameras and other research equipment, collected over 9,000 miles of data from over 200,000 rides on Virginia Tech’s Blacksburg campus. Deployment of the scooters began in August 2019. After being removed from campus during the COVID-19 pandemic, they were redeployed in August 2021 through the academic year.

“The e-scooter deployment at Virginia Tech collected the largest naturalistic e-scooter data set known to date and quantified the safety risks associated with behavioral, infrastructure, and environmental factors,” said Elizabeth White, programs and business manager for VTTI. “This was a very exciting research program to be a part of, and our collaboration with many departments on campus was invaluable to ensuring a safe deployment.

White was the lead researcher of the team that included six other Virginia Tech researchers and other industry experts. The results were recently published in published in the Journal of Safety Research.

Utilizing VTTI’s proprietary data acquisition system (DAS), researchers found that infrastructure-related factors, the behaviors of e-scooter riders and other around them, and environmental factors all created risk for e-scooter users. They found loss of control related to infrastructure was the greatest contributor, to all crash- and near-crash events, equating to 47 percent. In total, infrastructure caused 67 percent of incidents, followed by the presence of other road users at 19 percent and rider behavior at 14 percent.

Transitions from surfaces, such as moving from gravel or dirt to grass, proved to be the riskiest. Those riders were almost 60 times more likely to have a crash or near-crash experience. This was supported by data showing that riding off a designated path, or off-road, made users nearly 25 times more likely to experience such issues compared to those who rode on a shared-use path.

uring the study, there were no crashes between an e-scooter and a moving vehicle captured. Conflicts with other road users were shown to be more avoidable through evasive maneuvers when compared to infrastructure-related events. Researchers believe this is likely caused by riders misjudging the terrain or infrastructure or a lack of skill in navigating those obstacles.

VTTI pioneered DAS in the 1990s and it is frequently used by researchers to provide an in-depth look at driver behaviors. These systems allowed rider behavior, interactions with other road users, and other valuable safety data to be recorded and analyzed for various trends. To date, it has been used on everything from e-scooters to semi-trucks. For the e-scooter study, devices did not film the rider, just the riding behavior in order to maintain rider privacy. Riders also were limited to the Blacksburg campus.

To improve safety for riders, the research team recommends all riders engage in an educational outreach program that discusses the significant risks associated with infrastructure, behavior, and environmental factors. Meanwhile, VTTI and its partners will continue to study ways to improve safety around Blacksburg and beyond.

“We are in continued conversations with campus stakeholders to determine the future of micromobility on the Virginia Tech campus,” said White.

The project was funded in part by the Safety Through Disruption, a grant from the U.S. Department of Transportation’s University Transportation Centers program. The research was conducted in partnership with Ford and Spin.

Ford later sold off Spin.

“This discovery is truly captivating as it marks the very first detection of clumps around a young star that have the potential to give rise to giant planets,” says Alice Zurlo, a researcher at the Universidad Diego Portales, Chile, involved in the observations.

The work is based on a mesmerising picture obtained with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument on ESO’s VLT that features fascinating detail of the material around the star V960 Mon. This young star is located over 5000 light-years away in the constellation Monoceros and attracted astronomers’ attention when it suddenly increased its brightness more than twenty times in 2014. SPHERE observations taken shortly after the onset of this brightness ‘outburst’ revealed that the material orbiting V960 Mon is assembling together in a series of intricate spiral arms extending over distances bigger than the entire Solar System.

This finding then motivated astronomers to analyse archive observations of the same system made with ALMA, in which ESO is a partner. The VLT observations probe the surface of the dusty material around the star, while ALMA can peer deeper into its structure. “With ALMA, it became apparent that the spiral arms are undergoing fragmentation, resulting in the formation of clumps with masses akin to those of planets,” says Zurlo.

Astronomers believe that giant planets form either by ‘core accretion’, when dust grains come together, or by ‘gravitational instability’, when large fragments of the material around a star contract and collapse. While researchers have previously found evidence for the first of these scenarios, support for the latter has been scant.

“No one had ever seen a real observation of gravitational instability happening at planetary scales — until now,” says Philipp Weber, a researcher at the University of Santiago, Chile, who led the study published today in The Astrophysical Journal Letters.

“Our group has been searching for signs of how planets form for over ten years, and we couldn’t be more thrilled about this incredible discovery,” says team-member Sebastián Pérez from the University of Santiago, Chile.

ESO instruments will help astronomers unveil more details of this captivating planetary system in the making, and ESO’s Extremely Large Telescope (ELT) will play a key role. Currently under construction in Chile’s Atacama Desert, the ELT will be able to observe the system in greater detail than ever before, collecting crucial information about it. “The ELT will enable the exploration of the chemical complexity surrounding these clumps, helping us find out more about the composition of the material from which potential planets are forming,” concludes Weber.